Motor Control Flashcards
1
Q
Define motor control
A
Motor control is the subdiscipline of human movement studies concerned with understanding the processes that are responsible for the acquisition, performance and retention of motor skills.
2
Q
Define motor development
A
Deals with motor changes throughout the life span, specifically the changes in the acquisition, performance, and retention of motor skills that occur with growth, development, maturation and ageing.
3
Q
Define motor learning
A
Deals with motor control changes that occur as a consequence of practice (or adaption), focusing literally on how motor skills are learned and the changes in performance, retention, and control mechanisms that accompany skill acquisition.
4
Q
Other terms used to define motor control?
A
Motor behaviour Psychology of motor behaviour Motor learning and control Skill acquisition
5
Q
What does motor mean?
A
Movement
6
Q
What are motor skills?
A
Goal-directed actions that require movement of the whole body, limb, or muscle in order to be successfully performed
7
Q
What imaging techniques to physiologists use?
A
Magneic resonance imaging (mri) and positron emission tomography (pet scan)
8
Q
What equipment for physiologists use for measuring electrical activity in the brain?
A
Electroencephalography and magneto-encephalopathy
9
Q
What equipment for physiologists use for measuring electrical activity in the muscles?
A
Electromyography
10
Q
What are the neurological receivers?
A
Receptors
11
Q
What are the effectors in the body?
A
Muscles
12
Q
What is plasticity?
A
In the central nervous system, as in the communication network, it is the capacity for constant change
13
Q
How many neurons are there in the CNS?
A
Between 10^12 to 10^14 neurones
14
Q
How many (up to) synaptic connections with other neurons/receptors/motor units can neurons have?
A
Up to 10^4
15
Q
Two major subdivisions of the nervous system?
A
Central nervous system (CNS) Peripheral nervous system (PNS)
16
Q
What does the CNS consist of?
A
The brain and the spinal cord, responsible for overseeing and monitoring the activation of all sectors of the body, including muscles
17
Q
What does the PNS do?
A
Carries information from the sensory receptors to the central nervous system and commands from the central nervous system to the muscles.
18
Q
Two sensory outputs of the PNS?
A
Afferent and efferent
19
Q
Latin definition of afferent?
A
To carry forward
20
Q
Latin definition of efferent?
A
To carry away
21
Q
What does the cell body of a nerve do?
A
Containing the nucleus, regulates the homeostasis of the neuron
22
Q
What do dendrites do?
A
Collectively formed in a dendritic tree, connect with and receive information from other neurons, and in some cases, sensory receptors
23
Q
What does the axom do?
A
Responsible for sending information away from the neuron to other neurons
24
Q
What do the alpha motor neurons of the spinal cord do?
A
They possess many dendritic branches and a relatively long axon, also heavily branched to innervate multiple (100-15k) skeletal muscle fibres
25
What do gamma motor neurons do?
They are innervate contractile (intrafusal) fibres located in the muscle receptors. Consequently, they have considerably less-branched axons than do alpha motor neurones. Also located in the spinal cord.
26
What percentage of neurons in the spinal cord are gamma?
40%
27
What are pyramidal cells?
Located in the motor cortex of the brain; they funnel down to a single slender axom. Pyramidal cells send motor commands over the long distances from the brain to the spinal cord and may have axoms up to 1m in length.
28
Where are purkinje cells found?
In the cerebellum
29
What are Purkinje cells?
Single thin axom to which information is sent from an incredibly rich, systematically organised set of dendrites that provide these neurons with a characteristic tree-like appearance
30
What are interneurons?
A variety of shapes but typically have multiple dendrites and branching axoms that permit the connection of multiple neurons with multiple neurons
31
Where are interneurons formed and terminated?
Either in the brain and spinal cord
32
What are all neurons in the CNS surrounded by?
Other cells called glia or glial cells
33
What do glia/glial cells do?
They provide, among other things, the metabolic and immunological support for neurons
34
How do neurons carry messages?
From their dendrites to the terminal fibres of their axoms through a series of electrical pulses that are produced in the axom hillock
35
What does the electrical pulse produced by the axon hillock dependant on?
The sptial and temporal distribution of the pulses impinging on the cell body from its denritic tree
36
How to signals differentiate in weight in the neurons?
Signals arriving early and originating from dendrites close to the axon hillock carry more weight than do signals from distant neurons arriving late.
37
How does an axon hillock trigger a pulse?
When the summed weight of impulses reaching the neuron exceeds its threshold voltage
38
Where does a pulse of an axom hillock propagate to?
Along the axon to its terminus
39
What is myelin?
Fatty substances surrounding axoms
40
How do neurons pass information from one neuron to another?
Via Synapses
41
What does the greek original word for synapse mean?
Union
42
What is the gap between the presynaptic neuron and the postsynaptic neuron?
The synpatic cleft or junction
43
How does the electrical activity between neurons transmit?
Either by the direct spread of electrical current, or more frequently, the action of a chemical mediator called NEUROTRANSMITTER
44
What is acetycholine? (ACh)
A type of neurotransmitter (best known)
45
What is proprioception?
Information about the movement and orientation of the body and body parts in space
46
How is proprioception sensed?
Via kinesthetic receptors and vestibular receptors
47
What does the work kinesthesis derived from?
Move and sensation
48
What is the word proprioreception derived from?
Own
49
Where are kinesethic receptors?
Kinesthetic receptors are located in the muscles, tendons, joints and skin
50
Where are vestibular receptors located?
In the inner ear
51
What do vestibular receptors aid with?
Balance
52
What is acuity?
The highest level of visual sensitivity
53
Where is the highest density of photoreceptors?
The voea
54
Where do the majority of our optic nerves link between?
Areas of the midbrain (lateral geniculate nucleus) and the visual cortex (in the cerebrum)
55
Aside from the visual cortex and midbrain, where do the remaining optic nerves lie?
The superior colliculi (in the midbrain)
56
What do the nerves in the superior colliculi provide?
Ambient vision
57
What does focal vision do?
Specialised for recognising objects, distinguishing detail and assisting in the direct visual control of fine, precise movements (such as threading a needle)
58
What does ambient vision do?
Receives information from the whole of the retina, including the peripheral retina, and is concerned with the location of moving objects in the whole visual field. This pathway is especially implicated. Tion in sp and our rate of movement through the environment.
59
What does damage to the focal vision pathway ensue?
The inability to identify objects but the ability to located
60
What does damage to the ambient vision do?
Inability to locate objects though still have the ability to identify them
61
What is the principal source of sensory information from skeletal muscle?
Muscle spindle (a type of receptor)
62
Where would you find the most muscle spindles?
In the hand (fine motor control)
63
What are the two types of large muscle fibres in muscle spindles?
Extrafusal muscle fibres and intrafusal muscle fibres
64
How do intrafusal fibres differ from extrafusal fibres?
They are smaller (and incapable of directly causing whole muscle contraction) They are NOT innervated by alpha motor neurons but independently by gamma motor neurons (activity from brain not spine) When stimulated, contract only at endpoints, not whole length Have sensory receptors located along them and afferent connections back to the spinal cord
65
What are the receptors in tendons called?
Golgi tendon organs
66
What type of sensory output do golgi tendon organs emute?
Type 1b afferent fibres
67
What are some receptors on the skin?
Meissner’s corpuscles and Merkel’s discs
68
What are receptors wrapped around hair follicles?
Ruffini corpuscles
69
What receptors are located deeper in the skin and respond mostly to deep compression and high frequency vibrations?
Pacinian corpuscles
70
What are skin receptors called?
Cutaneous receptors
71
Three types of joint receptors?
Modified Ruffini Corpuscles, modified Pacinian ropuscles and Golgi Organs
72
Two types of versitular apparatus receptors?
The semicircular canals (superior, horizontal and posterior canals) Otilith Organs (the utricle and the saccule)
73
What does the semicircular canal respond to?
Angular acceleration in the three planes
74
What do the otolith organs respond to?
Linear acceleration
75
What is the size principle?
In natural movement, motor units are typically recruited in order of size; the motor units containing the smaller, less-forceful muscle fibres are recruited first. The order of activation is the size principle.
76
What are reflex movements?
Rapid movements occurring below the level of conciousness
77
Two main functions of the spinal cord?
Carries both input and output information from the sensory receptors to the brain and back to the muscles To support reflexes at the local spinal level to provide rapid, essentially automatic responding to noxious stimuli and to ensure the successful execution of movements already underway
78
How many spinal nerves are attached to the spine?
31
79
What part of the spinal nerve carries the efferent information?
The anterior (or ventral) root
80
What part of the spine carries afferent information?
The posterior (or dorsal) root
81
What does the anterior root comprise of?
Almost exclusively axons of alpha motor neurons, the cell bodies of which are located in the ventral horn
82
What is the posterior root comprised of?
Both the axons of the sensory neurons and their cell bodies, the latter clustered together to form the dorsal root ganglion
83
Latin origin meaning of reflex?
Reflexis - a bending back
84
What are the minimum of four basic nerve units needed to form a reflex arc?
A sensory receptor An afferent neuron An efferent neuron An effector
85
Simplest type of a reflex?
A monosynaptic reflex
86
Another word for the stretch reflex?
The mytotatic reflex
87
What is the reflex called when your limbs reflex away from pain or heat?
A flexion reflex
88
What is reciprocal inhibition?
During a flexion reflex, the rapid limb withdrawal is fascinated by the extensor musculature being turned off at the same time. This is achieved through interneronal inhibitory connections between the afferent neuron and the extensor motor neuron. (The neural control phenomena that ensures that agonist and antagonist muscles do not typically contract in opposition to each other.)
89
What does the crossed extensor reflex do?
Functions in conjunction with the flexion reflex to maintain posture (as in, another limb extending to support the body)
90
What are the five different types of reflexes of the spine?
Stretch reflex Flexion reflex Crossed extensor reflex Extensor thrust reflex Gait control
91
What is the extensor thrust reflex?
Aids in supporting the body’s weight against gravity
92
How does the extensor thrust reflex work?
Cutaneous receptors in the feet that are sensitive to pressure, cause reflex contraction of the extensor muscles of the leg. This reflex provides the foundation for standing balance without dependence on brain mechanisms.
93
How does a spinal cord assist with gait?
While it doesn’t initiate it (cutaneous receptors of the feet and the brain do), it preserves gait once it is initiated. (Can even transform from gait to running)
94
What is the spine often referred to as in the process of gait? (Walking)
The central pattern generator (since once gait is initiated, it repeats the pattern)
95
What is alpha-gamma co-activation?
The progress of any particular movement can be monitored and controlled through this process. In this process, actual muscle length is determined by contraction of extrafusal muscle fibres controlled by contraction of extrafusal muscle fibres controlled by the alpha motor neurons that originate at spinal level.
96
Where is the motor cortex?
Located immediately forward of the central sulcus in the frontal lobe of the cerebrum
97
Where is the cerebrum?
Located off the brain stem and below the occipital lobe of the cerebrum
98
Where is the basal ganglia?
Located in the inner layers of the cerebrum
99
Where is the brain stem?
Located forward of the cerebellum and continuous with the spinal cord and the cerebrum
100
What sections of the brain control motor functions?
The motor cortex, the central sulcus, the cerebellum, the basal ganglia and the brain stem
101
What percentage of neurons in the entire human nervous system does the motor cortex have?
Half of all the total neurons in the body
102
What link the two halves of the motor cortex?
The corpus callosum
103
Three sections of each cerebral hemisphere of the motor cortex?
Motor cortex, premotor cortex and a supplementary motor ara
104
What is Broca’s area?
Located only in the left hemisphere of the motor cortex, it has a critical role in the planning of the movements generating speech
105
Aside from the Broca’s area, what other specialised areas are in the premotor cortex?
Fronal eye fields
106
What two areas of the body take up two thirds of the motor cortex?
The hands and the mouth
107
What is the term used to describe how the left side of the body controls the right, and vice versa?
Contralateral movement
108
What parts of the motor cortex control muscles more proximal in the body?
It is possible for the muscle to appear on each hemisphere (ipsilaterally) and opposite at the same time (contralateral)
109
What is the most direct route of relaying commands to muscles?
The pyramidal tract (or the corticospinal tract). Allows neurons from the motor cortex to synapse directly in some cases with the alpha motor neurons at the spinal level.
110
What can damage to the pyramidal tract result in?
Hemiparesis or complete (heipledia) paralysis of contralateral movements
111
Alternate route to the pyramidal tract?
The extra-pyramidal tract
112
What is the extra-pyromidial tract?
Allows nerve impulses from the motor cortex to reach the spinal level through a range of pathways via the cerebellum, basal ganglia, THALAMUS and brain stem
113
What can damage to the extrapyramidal tract result in?
SPasticity
114
What ca damage to the cerebral cortex result in?
Apraxia
115
What does specific damage to the motor cortex result in?
Loss of fine-movement control
116
What does specific damage to the premotor cortex result in?
Results in a disruption to movement planning and selection, especially for gross movements involving a large number of muscle groups
117
What does specific damage to the supplementary motor cortex result in?
Disrupts the planning of sequential movements and performance of many tasks requiring bimanual coordination
118
Three types of fibres in the cerebellum?
Climbing fibres and mossy fibres, with the third output fibre being the Purinje cell
119
Two major outputs of the cerebellum?
The thalamus and the brain stem
120
What does the cerebellum do?
Regulation of muscle tone and coordinated smoothing of movements, timing and learning.
121
What are the five pairs of interconnected nuclei present in the basal ganglia?
The globus palidus, the caudate nucleus, the putamen, the subthalamic nucleus and the substantia nigra
122
Two main sources of input to the basal ganglia?
The motor areas of the cereral cortex and the brain stem
123
Two output locations of the basal ganglia?
The thalamus and the brain stem
124
Difference between cerebellum and basal ganglia?
Like the cerebellum, the basal ganglia, although not synapsing directly with spinal neurons, are able to influence alpha motor neuron activity though both the pyramidal tract and the rubrospinal tract.
125
Main function of the basal ganglia?
Despite knowledge of the obvious movement problems caused by dysfunction of the basal ganglia, the precise function of the basal ganglia in movement control remains elusive. Some favoured suggestions include the control of slow movements, the retrieval and initiation of movement plans, and the scaling of movement amplitudes (such as in writing)
126
Two well known, researched diseases of the basal ganglia?
Parkison’s disease and Huntigon’s disease
127
What is Parkison’s disease
A degenerative disease resulting from deficiency in the natural neurotransmitter substance dopamine that assist in carrying nerve impulses from one nucleus in the basal ganglia to another. symptons include shuffling, uncertain gait, limb tremors, difficult initiating movement etc
128
What is Huntington’s disease?
A hereditary degenerative disease resulting from damage to the dendrites that produce one of the neurotransmitters used to communicate between selected nuclei in the basal ganglia. Symptons include uncontrollable, involuntary rapid flicking movements of the limbs or facial muscles.
129
Three major areas of the brain stem responsible for motor control?
The pons, the medulla and the reticular formation
130
What do the pons and medulla receive information from?
The cerebral cortex, cerebellum and basal ganglia, along with the sensory systems.
131
What is the pons and medulla responsible for?
Integrating information from its inputs for output to the spinal cord for use in the control of many involuntary movements, such as those relating to posture and cardiorespiratory activity.
132
What reflexes are the brain stem responsible for?
The control of muscle tone and posture is fundamental to the operation of a number of spraspinal reflexes
133
Two examples of supraspinal reflexes?
The righting reflexes and the tonic reflexes
134
What is the righting reflex?
Maintains the orientation of the body with respect to gravity
135
What are tonic reflexes? What is an example of one?
The tonic neck reflex; it is concerned with the maintenance of the position of one body part in relation to another
136
What does damage to the pons or medulla result in?
Disrupts the control of involuntary movements and key orienting reflexes and endangers the control of vital physiological systems
137
What is the reticular formation?
A network of neurons that extend throughout the brain stem, and through its ascending connections to the cerebral cortex. Controls the cortex, and thus the state of arousal experience by the person
138
Basic information flow through the reticular formation?
Sensory detection -\> perceiving -\> interpretation -\> movement planning -\> programming of specific motor commands -\> Release of the commands of the spinal cord -\> Release of the commands to specific muscles -\> Observable movement
139
In the basic information flow through the reticular formation, what is the involved structure for sensory detection?
Sensory receptors
140
In the basic information flow through the reticular formation, what is the involved structure for perceiving?
Somatosensory cortex and other specialised cortices
141
In the basic information flow through the reticular formation, what is the involved structure for interpretation?
Parietal and occipital association cortex
142
In the basic information flow through the reticular formation, what is the involved structure for movement planning?
Prefrontral cortex ad association cortex
143
In the basic information flow through the reticular formation, what is the involved structure for programming of specific motor commands?
Supplementary motor cortex, basal ganglion and the cerebellum
144
In the basic information flow through the reticular formation, what is the involved structure for release of the commands to the spingal cord
Motor cortex, basal ganglia and the cerebellum
145
In the basic information flow through the reticular formation, what is the involved structure for release of the commands to specific muscles
Spinal cord
146
In the basic information flow through the reticular formation, what is the involved structure for observable movement
Motor units
147
Define degrees of freedom
Refers to the capability of the brain and nervous system to simultaneously and continuously consider, and somehow control, the enourmous number of independent variables that contribute to skilled movement.
148
Define motor equivalance
The capability of the motor system to perform a particular task, and produce the same movement outcome, in a variety of ways. Motor equivalence is a consequence of the many degrees of freedom we are able to independently control.
149
Define serial order
The capability of the motor system to structure movement commands in such a way as to reliably produce movement elements in their desired sequence.
150
What do serial-order errors in speech give rise to?
Spoonerisms (muman hovement intead of human movement)
151
What is the serial order error when typing cta instead of cat?
Transposition error
152
Define perceptual-motor integration
The capability of the motor system to produce movements closely matched to the current environmental demands (perceived by the performer)
153
Example of the perceptual motor integration?
If a walking surface becomes irregular we change our gait pattern
154
What is the key component to triggering the perceptual-motor integration
Perception and action
155
Define skill acquisition
The capability of the motor system to learn and improve, given appropriate conditions of practice
156
What are the three sequential processing stages of the CNS?
Perceiving, deciding and acting
157
What perception system detects smell?
Olfactory information
158
What perception system detects taste?
Gustatory information
159
Central processes of perception?
Detection (determining whether a signal is present) Comparison (determining whether two stimuli are the same or diff) Recognition (identifying stimuli, objects or patterns) Selective attention (Attending to one signal or event in preference to others)
160
What is CRT?
Choice Reaction Time
161
What is closed-loop control?
Control based on the monitoring of feedback
162
What is open-loop control?
Very rapid movements require all the efferent commands to be structured in advance. This process uses motor programs
163
Two principles of general motor development?
The caphalocaudal and proximodistal principles
164
What is the cephalocaudal principle?
Highlights that development proceeds in a hear-down manner; control develops first in the muscles of neck, then, in order, in the arms, trunk, and legs (sometimes kicking as a precursor for walking occurs)
165
What is the proxiomodistal principle?
The development progresses from the axis of the body outwards
166
Four stages to consider in development of motor skill?
Initial stage Elementary stage Mature stage Common problems
167
What is a scientist who studies aging?
A gerontologist
168
What category of human is likely to get postural sway?
Older people, and female
169
What conditions contribute to the increased loss of balance and falls among older people?
Poorer vision, increased use of medication, and changes in gait pattern that result in the foot being lifted less of the ground
170
Typical attributes of gait in the elderly?
Lift their feet less, walk slower, reduced range of motion at angle, greater out-toeing in foot placement
171
What are examples of a "smart" strategy?
Pacing effort to conserve energy Anticipating to avoid reaction time delays Using encoding strategies to improve memory
172
How much does a brain weigh at birth? What percentage of its size is it compared to adult?
300-350g, and its 25% it's adult weight though with all the neurons it'll ever need
173
What nerves decrease with age? what increases?
Nerve cells deplete at 10K cells a day; by 60-75 we lost 20% of all our nerve cells. Glial cells on the other hand increase with age. Thus, brain weight decreases.
174
What is the sharpness of vision called?
Visual acuity
175
What is an improve capability of adjusting the yes lens?
Accomodation
176
What percentage of vestibular receptors and nerve cells are lost by the age of 70?
40%
177
What percentage of sensory neurons are lost by the age 70? What is the condition called? What effect does this have?
30% are lost, innervating the peripheral receptors; condition called peripheral nephropathy
178
At what age do muscle fibres begin to differentiate?
Age 7 months old, with slow-twitch (type 1) making up 40% all fibers and fast-twitch (type 2) making up 45%. They reach steady state by age 3
179
What is the sucking reflex?
The reflex of a baby sucking the nipple
180
What is a doctor who specializes in the care of children?
A paediatrician
181
When do postural reflexes develop?
At 2 months of age
182
When do postural reflexes disappear? What replaces them?
After the first year of life and are progressively replaced by more voluntary movement control.
183
What is the walking and swimming reflex?
Locomotor reflexes
184
When do locomotor reflexes appear?
Present at birth or soon after
185
Do locomotor reflexes dissapear?
Yes, after 4-5 months of age, before walking or swimming are attempted.
186
Suggested role of postural and locomotor reflexes?
Preparing the nervous system for its pathways for the emergence of the voluntary fundamental motor skills.
187
Three general principles observed in the development of perceptual skills?
The maturation of perceptual skills continues well after the sensory system and receptors have mature structually. (maturity round 10yo) The more complex the perceptual judgement, the longer it takes the developing child to reach adult levels of performance. The integration of visual and kinesthetic information does not follow the individual maturation of the visual and kinesthetic systems but rather occurs simultaneously with it. (matures round 8yo)
188
When does acuity for moving objects occur?
After acuity for stationary objects occur
189
At what age does reaction time peak? When does it start to decline?
Just before 20 and around 20 it starts to decline
190
When 70-80 years of age, what young age equivalent is the reaction time equal to?
similar to one 5-6 years of age
191
Reaction time and movement time are very similar in their lifespan, except at what age?
18 years old, our reaction time tends to dip a little whereas movement time still improves, then at 20 years of age reaction time speeds up. Probably cause emotions idk
192
With aging comes a reduction in the number of functional neuromuscular units, and from ages 20-70 years old, what is the difference in neural stimulation needed to excite a muscle to contract?
At 70 years of age, it raises between 15-35% needed in order to stimulate a muscle contraction
193
Characteristics of experts?
Having all the time in the world Picking the right options Reading the situation well Being adaptable Moving in a smooth and easy manner Doing things automatically
194
What conflicting needs to skilled performers balance?
Fast yet accurate Consistent yet adaptable Maximally effective while expending minimum attention and effort
195
Three identifiable phases of transition from novice to expert
Verbal-cognitive phase Associative phase Autonomous phase
196
What is the verbal-cognitive phase?
The movement task to be learned is completely new to the individual. Processes are directed to placement of limbs, and gain constant feedback. Major activity is thinking. (strategies esp) Significant benefit from verbal feedback.
197
What is the associate phase?
Learns consequently spend majority of their time and effort fine-tuning the selected movement pattern rather than constantly switching from one movement to another. In this phase, there is no substitute for improvement aside from practice itself. Progression increases with task complexity.
198
What is the adaption phase?
Largely automatic, doesn't require attention. Open-loop control therefore largely replaces closed-loop control, and skilled performers have spare attention that can be allocated to other tasks.Downside is errors are ingrained.
199
The nerves in our arms and legs that we can palpate (feel) actually contain
Axons of both afferent and efferent neurons
200
Did the cerebral cortex evolved to allow humans better ability to produce fast and accurate body movements that are needed habitually?
False
201
Considering the human body as a closed loop control system, which of the following anatomical structures plays the role of the controller?
The CNS
202
Visual illusions tell us that:
Sensory information is incomplete and needs to be processed based on past experience and context to provide an internal representation of the world
203
Perception is:
A creative process that can allow us to infer features of a scene that are not physically there
204
What are reflex-voluntary movements?
initiated entirely from within the CNS performance improves with practice reflex and postural movements are often initiated that compensate for the effects of the intended action on other parts of the body
205
What type of person suffers from peripheral neurography?
Diabetes
206
What is peripheral neuropaphy?
Death of nerves in the vision
